linux-kernel - Re: [PATCH v1 2/3] driver core: Read atomic counter once in driver_probe

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Date:   Thu, 19 Mar 2020 00:49:09 +0100
From:   Ferry Toth <fntoth@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/3] driver core: Read atomic counter once in
 driver_probe_done()

Op 09-03-2020 om 15:11 schreef Andy Shevchenko:
> Between printing the debug message and actual check atomic counter can be
> altered. For better debugging experience read atomic counter value only once.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

Tested-by: Ferry Toth <fntoth@...il.com>

> ---
>   drivers/base/dd.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 43720beb5300..efd0e4c16ba5 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -669,9 +669,10 @@ static int really_probe_debug(struct device *dev, struct device_driver *drv)
>    */
>   int driver_probe_done(void)
>   {
> -	pr_debug("%s: probe_count = %d\n", __func__,
> -		 atomic_read(&probe_count));
> -	if (atomic_read(&probe_count))
> +	int local_probe_count = atomic_read(&probe_count);
> +
> +	pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
> +	if (local_probe_count)
>   		return -EBUSY;
>   	return 0;
>   }
>